That is a nice draft -- very complete and readable. I remember discussing
the out-of-order question with some of the CERN folks in October 1994 at
the Chicago WWW conference. The conclusion we came to was that it would
be easier to deploy SCP as an incompatible protocol than it would be to fix
all of the pre-standard HTTP/1.0 implementations, with more to gain from
doing the former. I suspect we are still at that state.
One thing I've toyed with in the past was to use a hierarchical request
ID as a poor man's form of transaction identifier. That is,
TID: 1234
would be a simple request #1234, whereas
TID: 888/1234
would indicate that request 1234 was part of transaction 888, and
TID: 7/888/1234
would be transaction 7, sub-transaction 888, request 1234. Naturally,
TID: http://example.com/7/888/1234
would be the globally unique identifier, if such were needed. Killing
two birds with one stone.
Cheers,
Roy T. Fielding, Chief Scientist, eBuilt, Inc.
2652 McGaw Avenue
Irvine, CA 92614-5840 fax:+1.949.609.0001
(fielding@ebuilt.com) <http://www.eBuilt.com>